水質汚濁斃死魚の死因判定法について-VIII : Phenolによる急性中毒死

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In this study, an attempt was made to detect phenol in the fish body killed by phenol solutions. The quantity of phenol was determined by the Gibbs method. Dissolve fish body in 10% sodium hydroxide. Distill after acidifing with phosphoric acid. Add 4ml of buffer solution to 80ml of distillate, and adjust pH from 9.2 to 9.6. Add 2ml of the Gibbs reagent. Hold the mixture for 1 hour in a 37°C incubator, and then cool to room temperature. Add 20ml of n-butyl alcohol and shake the mixture well. Separate the alcohol layer, and determine light absorption in 660mμ wave length. In these experiments the 48h TLm of rainbow trout, carp and Ayu fish (Plecoglossus altivelis) for phenol was about 4 ppm, 50 ppm and 9 ppm, respectively. Phenol was not present in the normal fish bodies, but it was clearly detected in the fish bodies killed by phenol solutions. It was also possible to detect phenol even after washing by running tap water for 24 hours after death. Phenol was detected in the skin, muscle, gill, digestive organs, liver, spleen and kidney of rainbow trout killed by phenol solution (Table 5), whereas it was not detected in the digestive organs, liver, spleen and kidney of animals kept in the solution for 5 hours after death by suffocation (Table 6). Thus it was concluded that this method could be used as one of the methods for postmortem identification of the pollutant in fish killed by water pollution.